Centrifugal fan-wheel



M. S. LEONARD.

ICENTRIFUGAL FAN WHEEL.

APPLICATION FILED 05c. 31. 1915.

1,33 1 ,07 1 Patented Feb. 17, 1920.

UNITED sTATEs PATENT OFFICE.

MERTON S. LEONARD, OF BOSTON, MASSACHUSETTS, ASSIGNOR. TO B. F. STURTEVANT COMPANY, OF BOSTON, MASSAQHUSETTS, A CORPORATION OF MASSACHUSETTS.

CENTRIFUGAL FAN -WI-IEEL.

Application filed December 31, 1915.

To all whom it may concern:

Be it known that I, MERTON S. LEONARD, a citizen of the United States, residing at Boston, in the county of Sufi'olk and State of Massachusetts, have invented certain new and useful Improvements in Centrifugal Fan-\Vheels; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The invention relates to centrifugal fan wheels which take the air in axially and discharge it circumferentially, and which are adapted for acting upon air carrying abrasive material which abrades or wears away the blades with which it comes in contact.

The object of the invention is to provide a novel and improved construction of fan wheel which will so distribute the abrasion caused by the abrasive material that the strength of the wheel will not be seriously affected thereby, and which will enable the wheel to be conveniently and economically repaired. To these ends the invention contemplates providing the wheel with a series of blades which extend inward beyond the inner edges of a series of intermediate blades and which are independent of the wheel supporting devices, and so securing the inwardly extending blades that they may be readily removed and replaced. With this construction, any abrasive material carried by the air entering the intake chamber of the wheel will be picked up and carried along over the faces of the inwardly extending blades before the air reaches the inner edges of the intermediate blades, so that the wear due to the abrasive material is practically confined to the inwardly extending blades. The wearing away of these blades will not materially affect the structural strength of the wheel or of its supporting devices, and the wheel may therefore remain in use without repair or danger of accident until the inwardly extending blades are substantially worn away. The worn blades may then be readily and quickly replaced by new blades, which will in turn be worn out and replaced, while the main structure of the wheel remains intact.

The invention will be readily understood Specification of Letters Patent.

Patented Feb. 17, 1920.

Serial No. 69,602.

from an inspection of the accompanying drawings and the following detailed description of the fan wheel illustrated therein.

In the drawings, Figure 1 is a side elevation of a fan wheel embodying the invention in its preferred form; Fig. 2 is a sectional view on line 22, Fig. 1; and Fig. 3 is a detailed sectional view on line 33, Fig. 1.

The invention is shown in the drawings as embodied in a high speed centrifugal blast fan adapted to handle or carry abrasive material or material in which abrasive foreign matter is liable to be present.

As shown, the wheel comprises the annular side blades 2 between which the blades of the fan are secured, and the central supporting spider having a hub 4E and radial arms 6, to the outer ends of which certain of the fan blades are secured. In the c0nstruction shown, every third blade 8 of the fan wheel extends in toward the center of the wheel beyond the inner edges of the intermediate blades 10 to which the arms of its supporting spider are connected, so that the inner portions of the blades 8 project into the intake chamber 12 of the wheel, and will pick up any abrasive material entering the intake chamber with the air before it has passed radially outward far enough to strike the inner portions of the shallower intermediate blades. The abrasive material will therefore be distributed on the inwardly projecting blades 8, and will abrade and wear away these blades to which the arms of the supporting spider are attached, while the intermediate blades will be practically unaffected. The wearing away of the blades 8 will not seriously weaken the wheel, since suflicient strength to withstand the strains developed during its use is afforded by the unworn intermediate blades, the side plates, and the supporting spider.

In order that the blades 8 may be readily removed when worn out, and replaced by new blades, they are provided with side flanges 12 which are secured to the side plates by bolts and nuts 14. Since the intermediate blades 10 form a permanent part of the wheel structure, their side flanges are preferably secured to the plates by rivets 16.

While it is preferred to employ the specific construction and arrangement of parts shown and described, it will be understood that this construction and arrangement is not essential to the broader features of the invention, and may be varied and modified without departing therefrom.

Having explained the nature and object of'the invention, and specifically described one form of mechanism in which it may be embodied, What is claimed is 1. A centrifugal fan wheel comprising a hub, spokes extending therefrom, side plates, air handling blades, means for permanently securing the spokes, plates and blades in proper relation, intermediate material handling blades, extending inwardly beyond said air handling blades for picking up and handling abrasive material, and means for removably securing the material handling blades to the side plates to permit the ready removal and replacement of said blades without disturbiiig the connections between the spokes, plates and air handling blades.

2. A centrifugal fan wheel comprising a hub, spokes extending therefrom, a driving blade permanently secured to each spoke, an annular side plate permanently secured to the axial ends of each of said blades, and a plurality of material handling blades for picking upon and handling abrasive material, said blades extending inwardly beyond 7 the driving blades and being located one between adjacent driving blades, and means for removably securingthe material handling blades to the side plates to permit the ready removal and replacement of the material handling blades without disturbing the connections of the driving blades with the spokes and with the side plates.

MERTON S. LEONARD.

It is hereby certified that in Letters Patent No. 1,331,071, granted Februar 17, 1920, upon the application of Merton S. Leonard, of Boston, Massachusetts, for an improvement in Centrifugal Fan-Wheels, errors appear in the printed specification requiring correction as follows: Page 1, lines 87-88, strike out the words to which the arms of the supporting spider are attached; same page, line 89, after the Word blades insert the Words to which the arms of the supporting spider are attached; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 30th day of March, A. D., 1920.

M. H. COULSTON,

Acting Commissioner of Patents.

[SEAL] 

